The Hadley family, George and Lydia and their children Peter and Wendy, live in an automated home that does everything for them. The children call to inform their parents they'll be late for supper, and Lydia asks George to take look at the nursery and suggests they have the family psychiatrist, David McLean come over. They check out the nursery and Lydia shows her husband the holographic image it's stuck on: an African veldt. George figures that they're getting their money's worth but Lydia has him wait. The landscape grows increasingly ominous as the vultures gather to eat something that the lions left behind. George starts to approach one of the lions and Lydia hastily grabs him and pulls him out of the room. As she locks the door, they hear growling on the other side.
Lydia grows increasingly panicked and insists they should shut down not just the room, but the entire automated house. She believes that they've gotten spoiled and should go on a vacation where they do things for themselves. George isn't convinced, and they're interrupted when the children call to say that they'll be later than they thought. Lydia orders them home immediately and they grudgingly agrees. Once they cut off, Lydia tells George to turn off the nursery for at least a couple of days. He goes to the room and tries to switch it to a different landscape, but the computer doesn't respond to his voice commands. He notices dirt on the otherwise sterile floor and repeats his order, but the lions continue eating something in the distance.
When Lydia learns what happened, she insists that the room is in a rut because the children have fixated on the veldt landscape, and Peter has programmed the room to stay on its current display. Peter and Wendy come home. However, when Lydia confronts them, Peter insists that they haven't been to African in weeks. Wendy runs on ahead to check and when the others arrive, the room is displaying a pastoral landscape. Lydia accuses Wendy of changing the program before they could get there. When the children deny it, Lydia orders them both to bed. As they go, George finds something on the floor: Lydia's old purse, covered in blood.
That night, Lydia goes to bed but is unable to sleep. She checks on the nursery and discovers it's reverted to the veldt. She quickly gets out and listens to the lions roaring on the other side.
The next day, George tells the children that they're going to shut down the nursery. When the children loudly object, George reluctantly compromises and says he'll leave it open as long as they visit different landscapes. Peter and Wendy agree and wonder if he's thinking about shutting down the house. When George admits he's thought about it, Peter abruptly tells him not to do it.
David McLean arrives and George and Lydia ask if he noticed anything unusual during the last family session. David assures them that a certain amount of paranoia and prosecution among children is typical, and they often manifest in nursery environments. The parents show David the nursery and after a few minutes, he tells them to shut it down because it's clear that the children hate George and Lydia and their hate is manifesting via the room. David tells them to get out and do something outside of the house and quit spoiling the children. George wonders if they should shut down the entire house, and if the nursery will hate him if he turns it off.
Peter and Wendy return and overhear the conversation. When they throw a tantrum, George shuts off first the nursery and then the entire house. The children run to the nursery and watch in horror as it powers down. They accuse their parents of killing the room, but Lydia insists that it's just a virtual reality. The children run off and David warns that George shouldn't have done it so abruptly. George disagrees and insists that they're now on vacation.
That night, George begins planning a skiing vacation. Lydia isn't convinced. Below, the house systems starts to activate again as the parental controls are shut down. The children start yelling from the nursery and their parents run to help them. They go into the room but the door locks behind them and Peter overrides the controls. George and Lydia pound on the door but it won't open, and the lions close in...
The next day, David arrives and realizes that the house has been turned back on. He goes to the nursery and finds Peter and Wendy having tea in the veldt landscape. David asks where their parents are, unaware of the blood on the door behind them. The children ignore his question and ask if he'd like some tea, while the door locks behind the psychiatrist.